Rosemary Ferguson slinks into the showroom in a short black pantsuit with that modelly nonchalance that makes everyone else instantly feel they have frizzed hair and sweat patches.

She is tall and brunette. Were it not for her strong nose and rickety smile she would be pretty. As it is these boyish imperfections upset the balance of her face, making it instead strikingly beautiful, in that edgy way that exploded in the Nineties when photographer Corinne Day and The Face magazine came together with a convergence of fashion constellations and her career was born. It was the era of grunge, when waifs like Rosemary, Kate Moss and Emma Balfour were suddenly in pictures everywhere smoking Marlboro Lights on crack mattress and squat sofas and showing nipples through sheer vests.

Today Rosemary is 38 and a long way from Nineties hedonism. She’s a nutrition specialist (as well as still modelling), and she’s married to artist Jake Chapman and mother of three daughters. She lives on the Oxford-Gloucestershire border, with two dogs (Jake’s Staffies) and a pony, converting all the old hell-raisers into juicing fanatics — zinging, energetic, morning-lovers — starting with her husband and not forgetting Kate Moss, her great friend (who, one likes to imagine, still slips a couple of vodka shots into her breakfast tomato juice when Rosemary’s not looking).

We’re in the studio of Folk, the tomboyish label she fronts, that is simple, androgynous East-End-art-scene hip, and novel in that it’s not allergic to using as models women who are the same age as its customers. Rails of the winter collection are all around, with the heady scent of thick cotton and lambs wool. She’s a fan of the brand — “it’s very cool” — but it’s hard to imagine trying anything on in 32 degrees of stifling heat.

Obviously I want to hear about Jake Chapman, her husband, who collaborates with his brother Dinos to create deliberately shocking pieces, such as mannequins of children with penises in place of noses. Reputedly he’s so tantrum-prone he makes Tracey Emin look mild. He threw a journalist out of his house for saying she didn’t like art jargon (“get out, just get the fuck out!”) and later wrote comparing her to a vagina with teeth.

So is he as obstreperous and cantankerous as he sounds? FolkClothing.com and image by Sam Green please?

“Yup,” she nods emphatically. Then laughs. “Actually he’s very passionate about what he does. I think people often go in expecting him to be really difficult and that obviously irritates him. He’s actually one of the funniest people I know. He’s very like, ‘I know what I’m talking about, I’ve worked very hard to know what I’m talking about so I’m not going to be belittled by someone. And if they try I’ll annihilate them.’”

I tell her how I met him once at a party a long time ago, when I had a black eye (hit accidentally by a flying object). She looks horrified, her palm leaping to her chest. “I thought you were going to say he gave it to you! Was he polite?” She checks. Yes, he complimented me on my shiner.

“He’s really clever,” she says. “He’s driven and he reads and reads. Philosophy is his passion. He talks to me about his ideas but his sounding board is Dinos. But we feel the same about things, you couldn’t live with him if you didn’t.” She makes a thumbing gesture to indicate that you’d be out on your ear.

He sounds tyrannical! Do they argue? “It can get quite heated sometimes,” she laughs. “We might suddenly discover that there’s a difference [of opinion], and that we have to work around each other and compromise.” She adds: “And not just about the kids, for our relationship too.” She plays with the yard of beads around her neck.

The daughter of a naval officer, Rosemary grew up first in Scotland, with an older brother and a twin brother, then in Rio, Brazil. After her parents separated, she moved to Farnham in Surrey. From then on her childhood was “very normal and provincial.” That is, until she was approached by Corinne Day in one of those fairy tale “discovery” stories that every teenage girl of a certain era wished for. “I was 15 and she found me in McDonald’s in Oxford Street, which is ironic considering what I do now.”

She signed with an agency and did “a couple of jobs, but I didn’t like it. I wanted to be down the pub with my friends,” so she quit. “And then when I was 17 I passed my driving test and needed a car so I called them back.”

A photo shoot for Yoji Yamamoto with the photographer David Sims, was her first booking, followed by French Vogue with Paolo Roversi, and, inevitably, a rapid rise followed: covers of British Vogue, i-D, The Face.

She deferred her place at London School of Economics to read English and psychology and moved to New York into a flat with David Sims, Emma Balfour and Guido Palau, the hairstylist. “I loved it because it wasn’t glamorous, it was grunge. There were a lot of girls like me: normal. The music was great, there was the Young British Artist scene,”[of which the Chapmans were a part. Designers like] “John Galliano and Alexander McQueen were emerging. The parties were fun — Halloween particularly. We’d get ridiculous outfits and Dianne Kendall would do our make up and Guido our hair and we’d look amazing.”

Modelling gave her the gap-year travel experiences — she went to Bolivia, and China “for Louis Vuitton. It was pretty incredible 15 years ago”. University fell by the wayside. She sensibly invested in a house in Islington (though her accountants said she’d “she’d never make a penny”) and sold it on for an enormous profit. At 24 she was pregnant by Barry Reigate, another artist — “Yes, I know, there’s a type going on!” Elfie (now 13, ) was born, but the couple split when she was one. Rosemary went to New York on September 10 2001 with the intention of moving back there to model but changed her mind the following day.

Two years later, she met Jake at a party. “Actually we got married really quickly — within 10 months. It was a rollercoaster.” They have Bliss, seven, and Blythe, six, born 14 months apart. They and Elfie were bridesmaids at Kate Moss’s wedding

Rosemary’s grandmother opened one of the first health food shops in the UK “called Spice of Life in Petersfield” and so it’s come full circle. “I think she’d be dead proud,” says Rosemary. “She was always very sure about health food. She wasn’t airy fairy: she was 6ft 2in and proper.” Rosemary advocates fasting and juicing and sees clients for one-to-one consultations (starting at £65).

Jake is her best client: “He’s obsessed. He puts me to shame. He’s really good, he doesn’t eat meat.” I’m relieved to hear he still likes the odd coffee. “He likes to feel well, the best he can feel. That’s basically what most people say — they’re tired of feeling rubbish. Tired of not sleeping, of stress. They want to lose weight.”

I mention a picture I’ve seen, in which he looks quite butch. She tells me off: “Actually he’s very handsome. He’s not butch any more — he’s Mr Healthy. He’s so lithe!” And Kate Moss? “We have been known to juice together, yes. She’s healthier than she’s made out to be.”

What about Rosemary, is she an evangelical puritan? “No. I do still drink alcohol — loads of it,” she jokes. “Not really loads — but I am human.”